Heimia alkaloids



United States Patent 3,184,446 IEEMIA ALKALQIDS Jerry A. Weisbach,Cherry Hill, N.J., assiguor to Smith Kline & French Laboratories,Philadelphia, Pa., a corporation of Pennsylvania No Drawing.Continuation of application Ser. No. 272,527, Apr. 12, 1963. Thisapplication July 15, 1963, Ser. No. 295,205

2 Claims. (Cl. 260-236) This invention relates to new crystallineproducts of manufacture and more specifically to new crystallinealkaloids of plants of the genus Heimia (family: Lythraceae). Thecrystalline alkaloids of this invention have useful diuretic activity. 7

The new alkaloids are produced from plants of two species of Heimia,namely Heimia salicz'folia and Heimfa myrtifolia, and are calledlythrine and lythridine. The ground whole plant material of Heimiasalicifolia is extracted with alcohol until removal of alkaloidalmaterial is complete. The residue obtained from the extract is treatedfirst with dilute tartaric acid solution and then a phosphoricacid-ethylacetate mixture. The combined filtered acid extracts at pH 8are extracted with chloroform, the residue from the organic layer isdissolved in acetic acid and the solution added to 10% sulfuric acidsolution. The filtered mixture is extracted with ether and the aqueouslayer at pH 8 is extracted with chloroform. Removal of the organicsolvent gives the alkaloidal material.

The solid dissolved in chloroform is chromatographed on 100200 meshFlorisil (magnesia-silica gel adsorbcut). The first fractions fromelution with chloroform containing 25% methanol give a singlecrystalline alkaloid, lythrine, C H NO melting at 24l242 C. It issoluble in the usual organic solvents such as chloroform, methylenechloride, dioxane, acetone and the like and in soluble in cold methanol,water or petroleum ether. Its ultraviolet absorption spectrum in ethanolexhibits the following characteristic maxima: max. A 260 m (log 5 4.08)and max. A 284 m (log e 4.14). The infrared ab sorption spectrumobtained in Nujol (a hydrocarbon oil) mull exhibits the followingcharacteristic bands (wavelengths expressed in microns): 2.72, 5.88 and6.23.

Continued elution with chloroform-methanol mixtures yields a crystallinealkaloid melting at 259-251" C. (dec.) identical with the alkaloidvertine described by Ferris, J. Org. Chem, vol. 27, pp. 2985-2990,September 1962. It is soluble in chloroform, methylene chloride, benzeneand methanol and insoluble in water or petroleum ether. Its ultravioletabsorption spectrum in ethanol exhibits the following characteristicmaxima: max. A 216 m (log 5 4.12) and max. a 284 mu (log 6 4.18). Theinfrared absorption spectrum (Nujol mull) exhibits the followingcharacteristic bands: 2.82, 5.86 and 6.25

The ground whole plant material of Heimia myrfifolz'a is extracted withethanol and worked up as described above to yield alkaloidal material.Chromatography on Florisil essentially as described above yieldslythrine in the early chloroform-5% methanol eluate, a new alkaloidlythridine in the initial chloroform-% methanol eluate and vertine inthe later fractions. The lythrine and vertine from both H. salicifolz'aand H. myrtifolia are identical.

The crystalline alkaloid lythridine melts at 2l8219 C. and analyzes foran empirical formula of C H NO It is soluble in chloroform, methanol,dioxane, acetone and methylene chloride and insoluble in petroleumether. Its ultraviolet absorption spectrum in ethanol exhibits acharacteristic maximum at a wavelength of 292 m (log 6 3.85). Theinfrared absorption spectrum (Nujol EJMAdfi Patented May 18, 1965 mull)exhibits the following characteristic bands: 2.72, 5.82 and 622g.

The new alkaloids of this invention have diuretic activity asdemonstrated in laboratory animals by standard procedures, for examplein rats after doses of 5-15 mg/kg. orally. These alkaloids constitute anew class of diuretics and are relatively free of toxic side effects.Particularly useful is the alkaloid lythrine.

For therapeutic use the alkaloids may be formulated into pharmaceuticalcompositions comprising the new crystalline alkaloid or a nontoxic acidaddition salt thereof and a pharmaceutical carrier. The compositionsthus provided by this invention may be in any dosage unit form suitablefor internal administration, for example tablets, capsules, solutions orsuspensions. The carrier may thus be a solid or liquid. If a solidcarrier is desired, the pure crystalline alkaloid is mixed with thecarrier, such as talc, mannitol, lactose or corn starch, and filled intoa soft gelatin capsule. Alternatively, the pure crystalline alkaloid ismixed with the carrier together with tableting aids, such as starch ormagnesium stearate, granulated using sucrose or gelatin soltuion andtableted. Suitable liquid carriers are peanut or vegetable oil which aremixed with the alkaloid and filled into soft gelatin capsules or waterto give a solution or suspension.

These compositions contain per dosage unit the desired therapeuticallyuseful amount of pure crystalline alkaloid. The advantages afforded bythis invention are obvious. Such compositions can be prepared containingexact amounts of the alkaloid to produce the desired diuretic effect.The uniformity and standardization of such effects as produced from thepure crystalline alkaloid is not possible with either the whole plantmaterial of H. salicifolia or H. myrtifolia or crude extracts thereof.

As indicated, the alkaloidal free bases may be used in the form of anontoxic acid addition salt. For example organic acids such as acetic,male'ic, fumaric, tartaric, citric, benzoic, methanesulfonic and thelike are reacted with the free base to give the corresponding salts.Similarly, inorganic acids such as hydrochloric, hydrobromic, sulfuric,phosphoric and the like are reacted with the free base to give thecorresponding salts. These salts are prepared by methods Well-known tothe art.

The following examples illustrate the production of lythrine andlythridine.

Example 1 A. The whole ground plant of Heimia salicifolia (14.5 kg.) isextracted with hot alcohol until the marc gives a negative alkaloidtest. The extract is concentrated in vacuo to a syrupy consistency andthe residual solvent is removed at 25 C. in a stream of air. The residueis treated with a total of 12 l. of warm 2% tartaric acid solution andthe mixture filtered with celite. A mixture of 0.2 M phosphoric acid andethyl acetate (3:2) is then added to the insoluble residue (3 2.5 l.)and the resultant mixture is stirred and heated at C. until the organicsolvent is removed. The cooled mixture is filtered and the filtratecombined with the tartaric acid extract. The combined acid extract ismade alkaline (pl-I 8) with concentrated ammonia solution and extractedwith chloroform. Evaporation of the extract in vacuo gives a pale greenfoam which is dissolved in 5010 ml. of acetic acid. The solution isadded with stirring to 4.2 l. of cold 10% sulfuric acid solution,filtered and the filtrate extracted with a total of 3 l. of ether. Theaqueous 7' layer is made alkaline (pH 8) with ammonia and extracted withchloroform. Removal of the solvent yields a tan, foamy alkaloidalmaterial (5 8 g.) which is dissolved in chloroform and chromatographedon a Florisil column (magnesia-silica gel adsorbent). The initialchloroform- 5% methanol eluate on combination and evaporation in vacuogives the crystalline alkaloid lythrine. Successive recrystallizationfrom chloroform-methanol and methylene chloride-petroleum ether producesfine, white needles, M.P. 24l242 C.; [a] =+40.6 (concentration: 0.3% inchloroform); Rcp value 2.01:0.09, where Rcp is defined as the ratio ofthe distance of movement of the thin layer spot of the compound to thedistance of movement of chlorpromazine on a silica gel G thin layerplate using a chloroform methanol eluent under standard conditions.

Analysis.-Calculated for C H NO C, 71.7; H, 6.7; N, 3.2; OCI-I(calculated for two), 14.25; CCH 6.2. Found: C, 71.6; H, 6.5; N, 3.3;OCH 14.46; C--CH none.

The ultraviolet spectrum of lythrine exhibits the followingcharacteristic maxima in ethanol:

max. A 260 m (log 6 4.08)

max. A 284 mp (log 6 4.14)

When suspended in a Nujol mull, absorption bands in the infrared regionof the spectrum are present at the following wavelengths expressed inmicrons: 2.72, 5.88 and 6.23.

The X-ray diifraction data obtained from lythrine (needles frommethylene chloride-petroleum ether) are as follows:

(1 (interplanar spacings I/Il (relative intensityin angstrom units)incident to difiracted rays) Reaction of the free base with a nontoxicorganic or inorganic acid as described hereinabove gives correspondingacid addition salts of lythrine. For example the hydrochloride salt isprepared by solution with gaseous hydrogen chloride and dilution withether. Recrystallization oflythrine hydrochloride from methanol producesWhite prisms, M.P. 300 C.

Analysis.Calculated for C H ClNO C, 66.1; H, 6.4; N, 3.0. Found: C,66.1; H, 6.4; N, 2.9.

Treatment of lythrine free base with acetic anhydridepyridine gives anacetate, M.P. 172-173 C.; [a]

+33.1 (concentration=0.75% in chloroform). Infrared bands (Nujol mull):5.59 and 5.87;.

B. Continued elution of the original alkaloidal material withchloroform-540% methanol mixtures yields the crystalline alkaloidvertine.

Example 2 The whole ground plant of Heimia myrtifolia (54 kg.) isextracted with 95% ethanol and worked up in the usual manner to yield afriable alkaloidal'material (75.2 g.). Chromatography of a portion ofthis.(60.8 g.) on Florisil, essentially as described in Example 1 above,yields lythxine (9.55, g.) in the chloroform to chloroform-% methanoleluate, a new alkaloid lythridine (1.60 g.) in the initialchloroform-10% methanol eluate and vertine (2.95 g.) in the remaininglater fractions. The identity of the lythrine and vertine obtained fromboth H. salicifolia and H. myrtifolia is established by melting points,mixed melting point determinations and by their superimposable X-raydiffraction patterns.

Recrystallization of lythridine from methanol-ethyl acerate-petroleumether gives white needles, M.P. 2l8-2l9 C.; [u] =-153.4(concentration=0.37% in chloroform); Rcp value 1.12:0.06.

Analysis.-Calculated for C H NO C, 68.0; H, 7.1; N, 3.2; OCH (calculatedfor two), 14.1. Found: C, 67.9; H, 7.2; N, 3.1; OCH 14.2.

The ultraviolet absorption spectrum of lythridine exhibits acharacteristic maximum in ethanol at a wavelength of 292 m (log 6 3.85).

' Infrared absorption bands (Nujol mull) are present at the followingwavelengths: 2.72, 5.82 and 622g.

The X-ray diffraction data obtained from lythridine (needles frommethanol-ethyl acetate-petroleum ether) are as follows:

d /Il The hydrochloride salt is prepared by solution of the base inmethanol, addition of gaseous hydrogen chloride and removal of thesolvent in vacuo. Recrystallization from methanol-chloroform-etheryields lythridine hydrochloride as white micro needles, M.P. 320 C.

Analysis.Calculated for C H ClNO C, 62.8; H, 6.5; N, 2.9. Found: C,62.8; H, 6.6; N, 2.9.

This application is a continuation of application Serial No. 272,527,filed April 12, 1963, now abandoned.

What is claimed is: 1. Lythrine, a crystalline substance analyzing forthe empirical formula C H NO being characterized by:

a melting point of 24l--242 C.;

an optical rotation as follows:

[a] =+40.6 (concentration=0.3% in chloroan ultraviolet absorptionspectrum in ethanol with the following maxima:

max. 260 m (log 6 408), and max. 284 mp. (log e 4.14); an infraredabsorption spectrum in a hydrocarbon oil with bands at the followingwavelengths, expressed in microns: 2.72, 5.88 and 6.23;

X-ray diffraction data as follows (needles from methylenechloride-petroleum ether):

d (angstrom I/I (relative units) intensity) a hydrochloride salt havinga melting point of 300 0.; and an acetate having:

a melting point of 172-173 C.; an optical rotation: [a] =+33.1(concentration=0.75% in chloroform); and infrared absorption bands atwavelengths of 5.59

and 5.87 microns. 2. Lythridine, a crystalline substance analyzing forthe empirical formula C H NO being characterized by:

a melting point of 218-219 (2.; an optical rotation as follows:

[a] =-153.4 (concentration: 0.37% in chloreform);

an ultraviolet absorption spectrum in ethanol with a 15 maximum at awavelength of 292 m (log .5 3.85);

an infrared absorption spectrum in a hydrocarbon oil with bands at thefollowing wavelengths, expressed in microns: 2.72; 5.82 and 6.22;

X-ray diffraction data as follows (needles from methanol-ethylacetate-petroleum ether):

d (angstrom I/Ii (relative units) intensity) and a hydrochloride salthaving a melting point of References Cited by the Examiner Ferris: Amer.Chem. Soc., Abstracts of Papers No. 141 (1962), page 134).

Ferris: J our. of Org. Chem., vol. 27 (1962), pages 29'85 2990.

20 IRVING MARCUS, Primary Examiner.

NICHOLAS S. RIZZO, Examiner.

1. LYTHRINE, A CRYSTALLINE SUBSTANCE ANALYZING FOR THE EMPIRICAL FORMULAC26H29NO5, BEING CHARACTERIZED BY: A MELTING POINT OF 241-242*C.; ANOPTICAL ROTATION AS FOLLOWS: (A)D25*=+40.6* (CONCENTRATION=0.3% INCHLOROFORM); AN ULTRAVIOLET ABSORPTION SPECTRUM IN ETHANOL WITH THEFOLLOWING MAXIMA: MAX.$ 260 MU (LOG E 408), AND MAX. $ 284 MU(LOG E4.14); AN INFRARED ABSORPTION SPECTRUM IN A HYDROCARBON OIL WITH BANDSAT THE FOLLOWING WAVELENGTHS, EXPRESSED IN MICRONS: 2.72, 5.88 AND 6.23;X-RAY DIFFRACTION DATA AS FOLLOWS (NEEDLES FROM METHYLENECHLORIDE-PETROLEUM ETHER): 10.10 75 9.00 75 8.30 45 6.70 65 6.20 45 5.79100 4.60 95 4.20 90 4.10 90 3.85 65 3.70 50